Characterization of yttrium as a getter material for hydrogen trapping in nuclear fusion applications

Yttrium is a promising candidate for use as a getter material in hydrogen isotope traps in liquid lithium circuits due to its strong affinity for hydrogen isotopes, particularly in the development of advanced nuclear fusion technologies. The surface properties of yttrium are critical to its gettering behavior, as they strongly influence the absorption and desorption of hydrogen. Certain surface treatments can amplify or inhibit hydrogen retention and desorption kinetics, with surface states being key factors in governing these interactions. Therefore, understanding the underlying mechanisms is essential for optimising the performance of yttrium getters in hydrogen traps, such as those envisaged for the Impurity Control System (ICS) of the IFMIF-DONES facility. This study investigated the impact of various yttrium surface treatments, such as chemical etching with hydrofluoric acid (HF) and mechanical polishing, on deuterium absorption. Spectroscopic and microscopic techniques were employed to analyse the treated surfaces. The results suggest that these treatments enhance the efficiency of deuterium absorption, with HF treatment yielding notably improved results. Furthermore, a comprehensive characterization of the modified metal surfaces was conducted to investigate the correlations between surface properties and the gettering performance of yttrium.